Smart and pH-sensitive rGO/Arabinoxylan/chitosan composite for wound dressing: In-vitro drug delivery, antibacterial activity, and biological activities

Synthesis of carboxymethyl chitosan-guar gum-poly(vinylpyrrolidone) ternary blended hydrogels with antibacterial/anticancer efficacy and drug delivery applications

Biopolymers have the utmost significance in biomedical applications and blending synthetic polymers has shown favorable characteristics versus individual counterparts. The utilization of the blends can be restricted through the use of toxic chemical agents such as initiators or crosslinkers. In this regard, a chemical agent-free ionizing irradiation is a beneficial alternative for preparing the hydrogels for biomedical applications. In this study, carboxymethyl chitosan (CM-CS), guar gum (GG), and poly(vinylpyrrolidone) (PVP) based ternary blends (TB) were crosslinked using various doses of ionizing irradiation to fabricate hydrogels. The prepared hydrogels were characterized for physicochemical properties, swelling analysis, biological assays, and drug delivery applications. Swelling analysis in distilled water revealed that the hydrogels exhibit excellent swelling characteristics. An in vitro cytocompatibility assay showed that the hydrogels have greater than 90% cell viability for the human epithelial cell line and a decreasing cell viability trend for the human alveolar adenocarcinoma cell line. In addition, the prepared hydrogels possessed excellent antibacterial characteristics against gram-positive Staphylococcus aureus (S. aureus) and gram-negative Escherichia coli (E. coli). Finally, the release studies of anti-inflammatory Quercus acutissima (QA) loaded hydrogels exhibited more than 80% release in phosphate-buffered saline (pH = 7.4). These findings suggest that TB hydrogels can be used as suitable carrier media for different release systems and biomedical applications.

Current progress of protein-based dressing for wound healing applications - A review

Protein-based wound dressings have garnered increasing interest in recent years owing to their distinct physical, chemical, and biological characteristics. The intricate molecular composition of proteins gives rise to unique characteristics, such as exceptional biocompatibility, biodegradability, and responsiveness, which contribute to the promotion of wound healing. Wound healing is an intricate and ongoing process influenced by multiple causes, and it consists of four distinct phases. Various treatments have been developed to repair different types of skin wounds, thanks to advancements in medical technology and the recognition of the diverse nature of wounds. This review has literature reviewed within the last 3-5 years-the recent progress and development of protein in wound dressings and the fundamental properties of an ideal wound dressing. Herein, the recent strides in protein-based state-of-the-art wound dressing emphasize the significant challenges and summarize future perspectives for wound healing applications.

Metal-organic frameworks: synthesis, properties, wound dressing, challenges and scopes in advanced wound dressing

Wound healing is a critical but complex biological process of skin tissue repair and regeneration resulting from various systems working together at the cellular and molecular levels. Quick wound healing and the problems associated with traditional wound repair techniques are being overcome with multifunctional materials. Over time, this research area has drawn significant attention. Metal-organic frameworks (MOFs), owning to their peculiar physicochemical characteristics, are now considered a promising class of well-suited porous materials for wound healing in addition to their other biological applications. This detailed literature review provides an overview of the latest developments in MOFs for wound healing applications. We have discussed the synthesis, essential biomedical properties, wound-healing mechanism, MOF-based dressing materials, and their wound-healing applications. The possible major challenges and limitations of MOFs have been discussed, along with conclusions and future perspectives. This overview of the literature review addresses MOFs-based wound healing from several angles and covers the most current developments in the subject. The readers may discover how the MOFs advanced this discipline by producing more inventive, useful, and successful dressings. It influences the development of future generations of biomaterials for the healing and regeneration of skin wounds.

Current Perspectives of Protein in Bone Tissue Engineering: Bone Structure, Ideal Scaffolds, Fabrication Techniques, Applications, Scopes, and Future Advances

In view of their exceptional approach, excellent inherent biocompatibility and biodegradability properties, and interaction with the local extracellular matrix, protein-based polymers have received attention in bone tissue engineering, which is a multidisciplinary field that repairs and regenerates fractured bones. Bone is a multihierarchical complex structure, and it performs several essential biofunctions, including maintaining mineral balance and structural support and protecting soft organs. Protein-based polymers have gained interest in developing ideal scaffolds as emerging biomaterials for bone fractured healing and regeneration, and it is challenging to design ideal bone substitutes as perfect biomaterials. Several protein-based polymers, including collagen, keratin, gelatin, serum albumin, etc., are potential materials due to their inherent cytocompatibility, controlled biodegradability, high biofunctionalization, and tunable mechanical characteristics. While numerous studies have indicated the encouraging possibilities of proteins in BTE, there are still major challenges concerning their biodegradability, stability in physiological conditions, and continuous release of growth factors and bioactive molecules. Robust scaffolds derived from proteins can be used to replace broken or diseased bone with a biocompatible substitute; proteins, being biopolymers, provide excellent scaffolds for bone tissue engineering. Herein, recent developments in protein polymers for cutting-edge bone tissue engineering are addressed in this review within 3-5 years, with a focus on the significant challenges and future perspectives. The first section discusses the structural fundamentals of bone anatomy and ideal scaffolds, and the second section describes the fabrication techniques of scaffolds. The third section highlights the importance of proteins and their applications in BTE. Hence, the recent development of protein polymers for state-of-the-art bone tissue engineering has been discussed, highlighting the significant challenges and future perspectives.

Graphene and its hybrid nanocomposite: A Metamorphoses elevation in the field of tissue engineering

In this discourse, we delve into the manifold applications of graphene-based nanomaterials (GBNs) in the realm of biomedicine. Graphene, characterized by its two-dimensional planar structure, superconductivity, mechanical robustness, chemical inertness, extensive surface area, and propitious biocompatibility, stands as an exemplary candidate for diverse biomedical utility. Graphene include various distinctive characteristics of its two-dimensional planar structure, enormous surface area, mechanical and chemical stability, high conductivity, and exceptional biocompatibility. We investigate graphene and its diverse derivatives, which include reduced graphene oxides (rGOs), graphene oxides (GOs), and graphene composites, with a focus on elucidating the unique attributes relevant to their biomedical utility. In this review article it highlighted the unique properties of graphene, synthesis methods of graphene and functionalization methods of graphene. In the quest for novel materials to advance regenerative medicine, researchers have increasingly turned their attention to graphene-based materials, which have emerged as a prominent innovation in recent years. Notably, it highlights their applications in the regeneration of various tissues, including nerves, skeletal muscle, bones, skin, cardiac tissue, cartilage, and adipose tissue, as well as their influence on induced pluripotent stem cells, marking significant breakthroughs in the field of regenerative medicine. Additionally, this review article explores future prospects in this evolving area of study.

Fabrication and characterization of a new eco-friendly sulfonamide-chitosan derivative with enhanced antimicrobial and selective cytotoxicity properties

Chitosan (CH) exhibits low antimicrobial activity. This study addresses this issue by modifying the chitosan with a sulfonamide derivative, 3-(4-(N,N-dimethylsulfonyl)phenyl)acrylic acid. The structure of the sulfonamide-chitosan derivative (DMS-CH) was confirmed using Fourier transform infrared spectroscopy and Nuclear magnetic resonance. The results of scanning electron microscopy, thermal gravimetric analysis, and X-ray diffraction indicated that the morphology changed to a porous nature, the thermal stability decreased, and the crystallinity increased in the DMS-CH derivative compared to chitosan, respectively. The degree of substitution was calculated from the elemental analysis data and was found to be moderate (42%). The modified chitosan exhibited enhanced antimicrobial properties at low concentrations, with a minimum inhibitory concentration (MIC) of 50 µg/mL observed for B. subtilis and P. aeruginosa, and a value of 25 µg/mL for S. aureus, E. coli, and C. albicans. In the case of native chitosan, the MIC values doubled or more, with 50 µg/mL recorded for E. coli and C. albicans and 100 μg/mL recorded for B. subtilis, S. aureus, and P. aeruginosa. Furthermore, toxicological examinations conducted on MCF-7 (breast adenocarcinoma) cell lines demonstrated that DMS-CH exhibited greater toxicity (IC50 = 225.47 μg/mL) than pure CH, while still maintaining significant safety limits against normal lung fibroblasts (WI-38). Collectively, these results suggest the potential use of the newly modified chitosan in biomedical applications.

Arabinoxylans matrixes as a potential material for drug delivery systems development - A bibliometric analysis and literature review

Arabinoxylans (AX) have become a focal point in the pharmaceutical sector owing to their physicochemical, biological, and functional properties. The purpose of this paper was to present a summary of the utilization of AX as drug release matrices through a bibliometric analysis (BA) and a literature review to spotlight the AX functional characteristics and their technological applications to promote this line of research. The BA was carried out using data from a Web of Science database research, specifically emphasizing the analysis of authors' keywords. This approach was chosen due to its significance in comprehensively understanding a particular research field and its relevance for in-depth knowledge of a research field. The BA outcomes revealed limited information concerning the AX applications in both release matrices and as excipients in the formulation and development of drug delivery systems (DDS), so there is a need for additional scientific and technological research in these areas to address the existing information gaps. However, the literature review shows that the native and modified AX from different delivery release systems, such as macrogels (including films, tablets, and hard gelatin capsules) and multi-particulate systems (including micro and nanogels), present an excellent potential as release matrices of biomolecules and drugs, such as doxorubicin, diclofenac sodium, caffeine, gentamicin, tizanidine hydrochloride, and insulin. In conclusion, AX have a wide potential for application in the pharmaceutical industry, so this work is expected to be a reference point for future research by scientists, technologists, and entrepreneurs who cope with the subject.

Development of nanocomposites based on chitosan/reduced graphene oxide for wound healing application

Nanocomposites containing different effective materials have various effects, such as antioxidant, and anti-inflammatory activity, which are desirable for wound dressing. Herein, nanocomposites based on chitosan/reduced graphene oxide (CS/rGO) containing curcumin (CS/rGO/Cur), curcumin and papain (CS/rGO/Cur/Pa), curcumin, papain, and collagen peptide (CS/rGO/CP/Cur/Pa), prepared using ionic gelation method and characterized by Fourier Transform Infrared (FTIR), Differential Light Scattering (DLS), X-ray diffraction (XRD), and Scanning Electron Microscope (SEM). Subsequently, the nanocomposite's potential for wound healing was studied through parameters such as porosity, swelling, degradability, anti-inflammatory, antioxidant, antibacterial, cell viability, and in-vivo. The results of FTIR, XRD, SEM, and DLS showed that the nanocomposites synthesized properly with an almost spherical morphology, an average diameter of below 100 nm (mostly 40-85 nm), and a hydrodynamic diameter of 455-616 nm. The various tests demonstrated the nanocomposite's effectiveness in wound healing. The results showed that CS/rGO/CP/Cur/Pa increased the anti-inflammatory and cell viability up to 99.7 % and 395 %, respectively, which is higher than others. Animal tests on rats showed that CS/rGO/CP/Cur/Pa accelerated the wound healing rate up to 70 %. In conclusion, the results showed that the nanocomposites based on CS/rGO significantly improve wound healing, and the presence of collagen peptides boost their wound healing potency.

The efficient role of sodium alginate-based biodegradable dressings for skin wound healing application: a systematic review

Injuries and damage to the skin can be caused by different reasons throughout human life. The use of sodium alginate in tissue dressing has been highly studied due to its intrinsic properties, including its degradation rate and biocompatibility, and the capacity of supporting tissue proliferation. The aim of this paper is to demonstrate evidences, through a systematic review method, to support the application of sodium alginate as a curative and as a potential accelerator in the healing of skin wounds. Four databases were used to develop this systematic review: Science Direct, PubMed, Scielo and Scopus. The time interval established for the search was from January 2016 to October 2023. After applying the exclusion and inclusion criteria, each selected article was evaluated and it was observed that the improvement of the mechanical properties of sodium alginate when correctly processed and crosslinked were evident. However, the increase of crosslinking affects as the wettability and the swelling of the biomaterials can cause limitations in mechanical properties and hidrophilic behavior. To achieve the ideal dressing, it is necessary to apply the optimal concentration of crosslinking and other substances, which can damage its hidrophilic characteristic. Thus, it was concluded that sodium alginate has every caracteristic desirable to develop an effective and safe dressing.

Recent antibacterial carbohydrate-based prodrugs, drugs and delivery systems to overcome antimicrobial resistance

Antimicrobial resistance is an increasing phenomenon that is threatening global health. Tuberculosis causative bacteria and several resistant and multidrug-resistant bacteria are widely spread and listed by the World Health Organization as global priorities for research and development. Hence, new antibacterial agents with new modes of action are urgently required. In this context, carbohydrate-based drugs have been extensively studied and used, presenting several benefits for therapeutical purposes. In this review, the latest efforts done in the carbohydrate-based antibacterial agents research field, reported from 2021 to 2023, are summarized. Carbohydrate-based prodrugs, drugs, and delivery systems are covered, highlighting derivatization of existing antibiotics, use of nanotechnology, and repurposing of available therapeutical agents as the most popular strategies used in antibacterial agents' development.

Exploring the efficacy of various wheat bran extracts in promoting burn wound healing: A comparative analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Although burn wound management in medical practice has improved, the challenge still exists and demands multidisciplinary participation. Wheat has been extensively used as a remedy of different skin conditions especially burns in almost all parts of Italy. However, the mechanism is still unclear.

AIM OF THE STUDY

To examine the effects of different wheat bran extracts on the healing of burn wound estimated grossly, histopathologically, and immunologically.

MATERIALS AND METHODS

Wistar male rats were divided into 5 groups; (control) saline treated group, Mebo (Moist Exposed Burn Ointment), cold-water extract, hot-water extract and methanolic extract groups. After the burn, four groups from the experimental groups were treated with Mebo, cold-water extract, hot-water extract and methanolic extract, respectively, but the negative-control group was treated daily with saline only. The observation was made along days 0, 5, 9, 13, 17 and 21. At the end of the study, rats were sacrificed, and blood samples were collected for biochemical and cytokines estimation in addition to wound samples were collected for histopathological and immunohistochemical studies.

RESULTS

The histopathological examination showed that the inflammation was significantly decreased in all extract-treated groups when compared with saline and Mebo-treated groups. Epithelial tissue and granulation tissue formation most significantly appeared in the cold water extract-treated group.

CONCLUSIONS

Cold water and methanolic extract groups showed the most rapid and effective healing of the burn wound. Particularly the cold-water extract, due to the sufficient concentration of zinc and phenolic components.

Fundamental properties of smart hydrogels for tissue engineering applications: A review

Tissue engineering is an advanced and potential biomedical approach to treat patients suffering from lost or failed an organ or tissue to repair and regenerate damaged tissues that increase life expectancy. The biopolymers have been used to fabricate smart hydrogels to repair damaged tissue as they imitate the extracellular matrix (ECM) with intricate structural and functional characteristics. These hydrogels offer desired and controllable qualities, such as tunable mechanical stiffness and strength, inherent adaptability and biocompatibility, swellability, and biodegradability, all crucial for tissue engineering. Smart hydrogels provide a superior cellular environment for tissue engineering, enabling the generation of cutting-edge synthetic tissues due to their special qualities, such as stimuli sensitivity and reactivity. Numerous review articles have presented the exceptional potential of hydrogels for various biomedical applications, including drug delivery, regenerative medicine, and tissue engineering. Still, it is essential to write a comprehensive review article on smart hydrogels that successfully addresses the essential challenging issues in tissue engineering. Hence, the recent development on smart hydrogel for state-of-the-art tissue engineering conferred progress, highlighting significant challenges and future perspectives. This review discusses recent advances in smart hydrogels fabricated from biological macromolecules and their use for advanced tissue engineering. It also provides critical insight, emphasizing future research directions and progress in tissue engineering.

Effect of hydrophobic property on antibacterial activities of green tea polysaccharide conjugates against Escherichia coli

We previously found that green tea polysaccharide conjugates (gTPCs) have antibacterial activity against Escherichia coli. In this study, the effect of hydrophobic property on the antibacterial activities of gTPCs was evaluated to elucidate their property-activity relationship. Three gTPCs (gTPCs-5 h, gTPCs-12 h and gTPCs-24 h) were extracted from green tea with the ethanol precipitation time of 5 h, 12 h and 24 h, respectively. These three gTPCs did not differ significantly in terms of molecular weight distribution, amino acids composition and zeta potentials. Fourier transform infrared spectroscopy results revealed that gTPCs-5 h and gTPCs-12 h processed more hydrogen bonds than gTPCs-24 h. The surface hydrophobicity and contact angle of gTPCs-5 h were larger than that of gTPCs-12 h and gTPCs-24 h. The antibacterial activity of gTPCs against E. coli decreased in the order of gTPCs-5 h > gTPCs-12 h > gTPCs-24 h. There wasn't significant difference among the zeta potentials of E. coli treated by gTPCs-5 h, gTPCs-12 h and gTPCs-24 h, but the bacterial contact angles of E. coli treated by gTPCs-5 h were higher compared with those of the other two gTPCs. Furthermore, gTPCs-5 h exhibited higher activity to decrease bacterial membrane proteins, and increase bacterial membrane permeability than the other two gTPCs. In conclusion, gTPCs with higher hydrophobicity property exhibited stronger antibacterial activity against E. coli.

The recent development of carbon-based nanoparticles as a novel approach to skin tissue care and management - A review

Since the skin is the first barrier of the body's defense against pathogens, delays in the healing process are affected by infections. Therefore, applying advanced substitute assistance improves the patient's quality of life. Carbon-based nanomaterials show better capabilities than conventional methods for managing skin wound infections. Due to their physicochemical properties such as small size, large surface area, great surface-to-volume ratio, and excellent ability to communicate with the cells and tissue, carbon-based nanoparticles have been considered in regenerative medicine. moreover, the carbon nano family offers attractive potential in wound healing via the improvement of angiogenesis and antibacterial compared to traditional approaches become one of the particular research interests in the field of skin tissue engineering. This review emphasizes the wound-healing process and the role of carbon-based nanoparticles in wound care management interaction with tissue engineering technology.

Ultrasonic neural regulation over two-dimensional graphene analog biomaterials: Enhanced PC12 cell differentiation under diverse ultrasond excitation

Two-dimensional (2D) biomaterials, with unique planar topology and quantum effect, have been widely recognized as a versatile nanoplatform for bioimaging, drug delivery and tissue engineering. However, during the complex application of nerve repair, in which inflammatory microenvironment control is imperative, the gentle manipulation and trigger of 2D biomaterials with inclusion and diversity is still challenging. Herein, inspired by the emerging clinical progress of ultrasound neuromodulation, we systematically studied ultrasound-excited 2D graphene analogues (graphene, graphene oxide, reduced graphene oxide (rGO) and carbon nitride) to explore their feasibility, accessibility, and adjustability for ultrasound-induced nerve repair in vitro. Quantitative observation of cell differentiation morphology demonstrates that PC12 cells added with rGO show the best compatibility and differentiation performance under the general ultrasound mode (0.5 w/cm2, 2 min/day) compared with graphene, graphene oxide and carbon nitride. Furthermore, the general condition can be improved by using a higher intensity of 0.7 w/cm2, but it cannot go up further. Later, ultrasonic frequency and duty cycle conditions were investigated to demonstrate the unique and remarkable inclusion and diversity of ultrasound over conventional electrical and surgical means. The pulse waveform with power of 1 MHz and duty cycle of 50 % may be even better, while the 3 MHz and 100 % duty cycle may not work. Overall, various graphene analog materials can be regarded as biosafe and accessible in both fundamental research and clinical ultrasound therapy, even for radiologists without material backgrounds. The enormous potential of diverse and personalized 2D biomaterials-based therapies can be expected to provide a new mode of ultrasound neuromodulation.

Graphene Oxide-Functionalized Bacterial Cellulose-Gelatin Hydrogel with Curcumin Release and Kinetics: In Vitro Biological Evaluation

Biopolymer-based bioactive hydrogels are excellent wound dressing materials for wound healing applications. They have excellent properties, including hydrophilicity, tunable mechanical and morphological properties, controllable functionality, biodegradability, and desirable biocompatibility. The bioactive hydrogels were fabricated from bacterial cellulose (BC), gelatin, and graphene oxide (GO). The GO-functionalized-BC (GO-f-BC) was synthesized by a hydrothermal method and chemically crosslinked with bacterial cellulose and gelatin using tetraethyl orthosilicate (TEOS) as a crosslinker. The structural, morphological, and wettability properties were studied using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and a universal testing machine (UTM), respectively. The swelling analysis was conducted in different media, and aqueous medium exhibited maximum hydrogel swelling compared to other media. The Franz diffusion method was used to study curcumin (Cur) release (Max = 69.32%, Min = 49.32%), and Cur release kinetics followed the Hixson-Crowell model. Fibroblast (3T3) cell lines were employed to determine the cell viability and proliferation to bioactive hydrogels. Antibacterial activities of bioactive hydrogels were evaluated against infection-causing bacterial strains. Bioactive hydrogels are hemocompatible due to their less than 0.5% hemolysis against fresh human blood. The results show that bioactive hydrogels can be potential wound dressing materials for wound healing applications.

GPP-TSAIII nanocomposite hydrogel-based photothermal ablation facilitates melanoma therapy

BACKGROUND

Photothermal therapy (PTT) is a promising cancer treatment, but its application is limited by low photoconversion efficiency. In this study, we aimed to develop a novel graphene oxide (GO)-based nanocomposite hydrogel to improve the bioavailability of timosaponin AIII (TSAIII) while maximizing PTT efficacy and enhancing the antitumor effect.

METHODS

GO was modified via physical cross-linking with polyvinyl alcohol. The pore structure of the gel was adjusted by repeated freeze-thawing and the addition of polyethylene glycol 2000 to obtain a nanocomposite hydrogel (GPP). The GPP loaded with TSAIII constituted a GPP-TSAIII drug delivery system, and its efficacy was evaluated by in vitro cytotoxicity, apoptosis, migration, and uptake analyses, and in vivo antitumor studies.

RESULTS

The encapsulation rate of GPP-TSAIII was 66.36 ± 3.97%, with slower in vitro release and higher tumor cell uptake (6.4-fold) compared to TSAIII. GPP-TSAIII in combination with PTT showed better bioavailability and antitumor effects in vivo than did TSAIII, with a 1.9-fold higher tumor suppression rate than the TSAIII group.

CONCLUSIONS

GPP is a potential vehicle for delivery of TSAIII-like poor water-soluble anticancer drugs. The innovative PTT co-delivery system may serve as a safe and effective melanoma treatment platform for further anticancer translational purposes.

Fabrication of PCL/CMARX/GO Composite Nanofibrous Mats for Dye Adsorption: Wastewater Treatment

The effluents of industrial wastewater contain several toxic organic and inorganic pollutants that may contaminate clean and freshwater sources if untreated or poorly treated. These toxic pollutants include colors; hazardous compounds; surfactants; cosmetics; agrochemicals; pharmaceutical by-products; and agricultural, pharmaceutical, and medical contaminants. Treating wastewater has become a global problem. Many projects have been started in the last two decades to treat wastewater, resultant water pollution, and associated waste management problems. Adsorbants based on graphene oxide (GO) are viable wastewater treatment materials due to their adaptability, photocatalytic action, and capacity for self-assembly. Here, we report the fabrication of nanofibrous mats from polycaprolactone (PCL), carboxymethyl arabinoxylan (CMARX), and carboxyl-functionalized-graphene oxide using an electrospinning technique. The silver nanoparticles were loaded onto the mat to enhance their photocatalytic activity. These mats were characterized using different techniques, including Fourier transform infrared (FTIR), scanning electron microscope (SEM), and transmission electron microscope (TEM). The water contact angles were used to study their hydrophilic and hydrophobic behavior. The Langmuir isotherm model and adsorption kinetics were studied to evaluate their adsorption capabilities against methylene blue (MB). Sample 2 followed the Langmuir isotherm model (R² = 0.9939). Adsorption kinetics exhibited pseudo-second order behavior (R² = 0.9978) due to their maximum correlation coefficient values. MB has excellent adsorption at room temperature and the formation of the monolayer at the surface of the adsorption mat. An enhanced PO₄^3- and MB adsorption was observed, providing recyclability up to 4-5 times. Hence, the fabricated nanofibrous mat would be a potential candidate for more effective wastewater treatment applications.

Role of Graphene Oxide in Bacterial Cellulose-Gelatin Hydrogels for Wound Dressing Applications

Biopolymer-based hydrogels have several advantages, including robust mechanical tunability, high biocompatibility, and excellent optical properties. These hydrogels can be ideal wound dressing materials and advantageous to repair and regenerate skin wounds. In this work, we prepared composite hydrogels by blending gelatin and graphene oxide-functionalized bacterial cellulose (GO-f-BC) with tetraethyl orthosilicate (TEOS). The hydrogels were characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), atomic force microscope (AFM), and water contact angle analyses to explore functional groups and their interactions, surface morphology, and wetting behavior, respectively. The swelling, biodegradation, and water retention were tested to respond to the biofluid. Maximum swelling was exhibited by GBG-1 (0.01 mg GO amount) in all media (aqueous = 1902.83%, PBS = 1546.63%, and electrolyte = 1367.32%). All hydrogels were hemocompatible, as their hemolysis was less than 0.5%, and blood coagulation time decreased as the hydrogel concentration and GO amount increased under in vitro standard conditions. These hydrogels exhibited unusual antimicrobial activities against Gram-positive and Gram-negative bacterial strains. The cell viability and proliferation were increased with an increased GO amount, and maximum values were found for GBG-4 (0.04 mg GO amount) against fibroblast (3T3) cell lines. The mature and well-adhered cell morphology of 3T3 cells was found for all hydrogel samples. Based on all findings, these hydrogels would be a potential wound dressing skin material for wound healing applications.

Recent progress of antibacterial hydrogels in wound dressings

Hydrogels are essential biomaterials due to their favorable biocompatibility, mechanical properties similar to human soft tissue extracellular matrix, and tissue repair properties. In skin wound repair, hydrogels with antibacterial functions are especially suitable for dressing applications, so novel antibacterial hydrogel wound dressings have attracted widespread attention, including the design of components, optimization of preparation methods, strategies to reduce bacterial resistance, etc. In this review, we discuss the fabrication of antibacterial hydrogel wound dressings and the challenges associated with the crosslinking methods and chemistry of the materials. We have investigated the advantages and limitations (antibacterial effects and antibacterial mechanisms) of different antibacterial components in the hydrogels to achieve good antibacterial properties, and the response of hydrogels to stimuli such as light, sound, and electricity to reduce bacterial resistance. Conclusively, we provide a systematic summary of antibacterial hydrogel wound dressings findings (crosslinking methods, antibacterial components, antibacterial methods) and an outlook on long-lasting antibacterial effects, a broader antibacterial spectrum, diversified hydrogel forms, and the future development prospects of the field.

pH-Responsive wound dressings: advances and prospects

Wound healing is a complex and dynamic process, in which the pH value plays an important role in reflecting the wound status. Wound dressings are materials that are able to accelerate the healing process. Among the multifunctional advanced wound dressings developed in recent years, pH-responsive wound dressings, especially hydrogels, show great potential owing to their unique properties of adjusting their functions according to the wound conditions, thereby allowing the wound to heal in a regulated manner. However, a comprehensive review of pH-responsive wound dressings is lacking. This review summarizes the design strategies and advanced functions of pH-responsive hydrogel wound dressings, including their excellent antibacterial properties and significant pro-healing abilities. Other advanced pH-responsive materials, such as nanofibers, composite films, nanoparticle clusters, and microneedles, are also classified and discussed. Next, the pH-monitoring functions of pH-responsive wound dressings and the related pH indicators are summarized in detail. Finally, the achievements, challenges, and future development trends of pH-responsive wound dressings are discussed.

Conductive hydrogels for tissue repair

Conductive hydrogels (CHs) combine the biomimetic properties of hydrogels with the physiological and electrochemical properties of conductive materials, and have attracted extensive attention in the past few years. In addition, CHs have high conductivity and electrochemical redox properties and can be used to detect electrical signals generated in biological systems and conduct electrical stimulation to regulate the activities and functions of cells including cell migration, cell proliferation, and cell differentiation. These properties give CHs unique advantages in tissue repair. However, the current review of CHs is mostly focused on their applications as biosensors. Therefore, this article reviewed the new progress of CHs in tissue repair including nerve tissue regeneration, muscle tissue regeneration, skin tissue regeneration and bone tissue regeneration in the past five years. We first introduced the design and synthesis of different types of CHs such as carbon-based CHs, conductive polymer-based CHs, metal-based CHs, ionic CHs, and composite CHs, and the types and mechanisms of tissue repair promoted by CHs including anti-bacterial, antioxidant and anti-inflammatory properties, stimulus response and intelligent delivery, real-time monitoring, and promoted cell proliferation and tissue repair related pathway activation, which provides a useful reference for further preparation of bio-safer and more efficient CHs used in tissue regeneration.

Aptamers as Novel Binding Molecules on an Antimicrobial Peptide-Armored Composite Hydrogel Wound Dressing for Specific Removal and Efficient Eradication of Pseudomonas aeruginosa

Here we present for the first time a potential wound dressing material implementing aptamers as binding entities to remove pathogenic cells from newly contaminated surfaces of wound matrix-mimicking collagen gels. The model pathogen in this study was the Gram-negative opportunistic bacterium Pseudomonas aeruginosa, which represents a considerable health threat in hospital environments as a cause of severe infections of burn or post-surgery wounds. A two-layered hydrogel composite material was constructed based on an established eight-membered focused anti-P. aeruginosa polyclonal aptamer library, which was chemically crosslinked to the material surface to form a trapping zone for efficient binding of the pathogen. A drug-loaded zone of the composite released the C14R antimicrobial peptide to deliver it directly to the bound pathogenic cells. We demonstrate that this material combining aptamer-mediated affinity and peptide-dependent pathogen eradication can quantitatively remove bacterial cells from the "wound" surface, and we show that the surface-trapped bacteria are completely killed. The drug delivery function of the composite thus represents an extra safeguarding property and thus probably one of the most important additional advances of a next-generation or smart wound dressing ensuring the complete removal and/or eradication of the pathogen of a freshly infected wound.

Substance P&dimethyloxallyl glycine-loaded carboxymethyl chitosan/gelatin hydrogel for wound healing

Recent efforts have focused on preparing drug-loaded hydrogel for wound healing. In order to obtain an ideal hydrogel dressing for skin wound repair, a carboxymethyl chitosan-gelatin hydrogel was prepared for co-delivery of SP (substance P) and DMOG (dimethyloxallyl glycine) by a chemical cross-linking method using genipin as the cross-linking agent. The synthesized hydrogels have good biocompatibility and physicochemical properties due to the low toxicity of the hydrogel material. The three-dimensional network structure of the hydrogels supports cell migration and proliferation, and the combination of SP and DMOG drugs exhibited strong effects on cell proliferation. Moreover, the co-loaded drug hydrogels could significantly promote wound healing in vivo, and provide a potential hydrogel for wound healing.

Reduced graphene oxide-enriched chitosan hydrogel/cellulose acetate-based nanofibers application in mild hyperthermia and skin regeneration

Asymmetric wound dressings have captured researchers' attention due to their ability to reproduce the structural and functional properties of the skin layers. Furthermore, recent studies also report the benefits of using near-infrared (NIR) radiation-activated photothermal therapies in treating infections and chronic wounds. Herein, a chitosan (CS) and reduced graphene oxide (rGO) hydrogel (CS_rGO) was combined with a polycaprolactone (PCL) and cellulose acetate (CA) electrospun membrane (PCL_CA) to create a new NIR-responsive asymmetric wound dressing. The rGO incorporation in the hydrogel increased the NIR absorption capacity and allowed a mild hyperthermy effect, a temperature increase of 12.4 °C when irradiated with a NIR laser. Moreover, the PCL_CA membrane presented a low porosity and hydrophobic nature, whereas the CS_rGO hydrogel showed the ability to provide a moist environment, prevent exudate accumulation and allow gaseous exchanges. Furthermore, the in vitro data demonstrate the capacity of the asymmetric structure to act as a barrier against bacteria penetration as well as mediating a NIR-triggered antibacterial effect. Additionally, human fibroblasts were able to adhere and proliferate in the CS_rGO hydrogel, even under NIR laser irradiation, presenting cellular viabilities superior to 90 %. Altogether, our data support the application of the NIR-responsive asymmetric wound dressings for skin regeneration.

Graphene-Based Materials for Inhibition of Wound Infection and Accelerating Wound Healing

Bacterial infection of the wound could potentially cause serious complications and an enormous medical and financial cost to the rapid emergence of drug-resistant bacteria. Nanomaterials are an emerging technology, that has been researched as possible antimicrobial nanomaterials for the inhibition of wound infection and enhancement of wound healing. Graphene is 2-dimensional (2D) sheet of sp² carbon atoms in a honeycomb structure. It has superior properties, strength, conductivity, antimicrobial, and molecular carrier abilities. Graphene and its derivatives, Graphene oxide (GO) and reduced GO (rGO), have antibacterial activity and could damage bacterial morphology and lead to the leakage of intracellular substances. Besides, for wound infection management, Graphene-platforms could be functionalized by different antibacterial agents such as metal-nanoparticles, natural compounds, and antibiotics. The Graphene structure can absorb near-infrared wavelengths, allowing it to be used as antimicrobial photodynamic therapy. Therefore, Graphene-based material could be used to inhibit pathogens that cause serious skin infections and destroy their biofilm community, which is one of the biggest challenges in treating wound infection. Due to its agglomerated structure, GO hydrogel could entrap and stack the bacteria; thus, it prevents their initial attachment and biofilm formation. The sharp edges of GO could destroy the extracellular polymeric substance surrounding the biofilm and ruin the biofilm biomass structure. As well as, Chitosan and different natural and synthetic polymers such as collagen and polyvinyl alcohol (PVA) also have attracted a great deal of attention for use with GO as wound dressing material. To this end, multi-functional polymers based on Graphene and blends of synthetic and natural polymers can be considered valid non-antibiotic compounds useful against wound infection and improvement of wound healing. Finally, the global wound care market size was valued at USD 20.8 billion in 2022 and is expected to expand at a compound annual growth rate (CAGR) of 5.4% from 2022 to 2027 (USD 27.2 billion). This will encourage academic as well as pharmaceutical and medical device industries to investigate any new materials such as graphene and its derivatives for the treatment of wound healing.

Fast and Sustained Axonal Growth by BDNF Released from Chitosan Microspheres

Brain-derived neurotrophic factor (BDNF) regulates dendritic branching and dendritic spine morphology, as well as synaptic plasticity and long-term potentiation. Consequently, BDNF deficiency has been associated with some neurological disorders such as Alzheimer's, Parkinson's or Huntington's diseases. In contrast, elevated BDNF levels correlate with recovery after traumatic central nervous system (CNS) injuries. The utility of BDNF as a therapeutic agent is limited by its short half-life in a pathological microenvironment and its low efficacy caused by unwanted consumption of non-neuronal cells or inappropriate dosing. Here, we tested the activity of chitosan microsphere-encapsulated BDNF to prevent clearance and prolong the efficacy of this neurotrophin. Neuritic growth activity of BDNF release from chitosan microspheres was observed in the PC12 rat pheochromocytoma cell line, which is dependent on neurotrophins to differentiate via the neurotrophin receptor (NTR). We obtained a rapid and sustained increase in neuritic out-growth of cells treated with BDNF-loaded chitosan microspheres over control cells (p < 0.001). The average of neuritic out-growth velocity was three times higher in the BDNF-loaded chitosan microspheres than in the free BDNF. We conclude that the slow release of BDNF from chitosan microspheres enhances signaling through NTR and promotes axonal growth in neurons, which could constitute an important therapeutic agent in neurodegenerative diseases and CNS lesions.

Shape-Memory-Reduced Graphene/Chitosan Cryogels for Non-Compressible Wounds

In this study, an antibacterial and shape-memory chitosan cryogel with high blood absorption and fast recovery from non-compressible wounds was prepared using a one-step method. Herein, we prepared a shape-memory-reduced graphene/chitosan (rGO-CTS) cryogel using a one-step method with a frozen mixing solution of chitosan, citric acid, dopamine, and graphene oxide, before treating it with alkaline solutions. The alkaline solution not only promoted the double cross-linking of chitosan but also induced dopamine to form polydopamine-reducing graphene oxide. Scanning electron microscope (SEM) images showed that the rGO-CTS cryogel possessed a uniform porous network structure, attributing excellent water-induced shape-memory properties. Moreover, the rGO-CTS cryogel exhibited good mechanical properties, antibacterial activity, and biocompatibility. In mouse liver trauma models, the rGO-CTS cryogel showed good blood clotting and hemostatic capabilities. Therefore, this composite cryogel has great potential as a new hemostatic material for application to non-compressible wounds.

Self-Assembled Nanofibrous Membranes by Electrospinning as Efficient Dye Photocatalysts for Wastewater Treatment

Water pollution has become a leading problem due to industrial development and the resulting waste, which causes water contamination. Different materials and techniques have been developed to treat wastewater. Due to their self-assembly and photocatalytic behavior, membranes based on graphene oxide (GO) are ideal composite materials for wastewater treatment. We fabricated composite membranes from polylactic acid (PLA) and carboxylic methyl cellulose (CMC)/carboxyl-functionalized graphene oxide (GO-f-COOH) using the electrospinning technique and the thermal method. Then, a nanofibrous membrane (PLA/CMC/GO-f-COOH@Ag) was produced by loading with silver nanoparticles (Ag-NPs) to study its photocatalytic behavior. These membranes were characterized using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) in order to investigate the behavior of the fabricated membranes. The degradation kinetics studies were conducted using mathematical models, such as the pseudo first- and second-order models, by calculating their regression coefficients (R²). These membranes exhibited exceptional dye degradation kinetics. The R² values for pseudo first order were PCGC = 0.983581, PCGC@Ag = 0.992917, and the R² values for pseudo second order were PCGC = 0.978329, PCGC@Ag = 0.989839 for methylene blue. The degradation kinetics of Rh-B showed R² values of PCGC = 0.973594, PCGC@Ag = 0.989832 for pseudo first order and R² values of PCGC = 0.994392, PCGC@Ag = 0.998738 for pseudo second order. The fabricated nanofibrous membranes exhibited a strong π-π electrostatic interaction, thus providing a large surface area, and demonstrated efficient photocatalytic behavior for treating organic dyes present in wastewater. The fabricated PLA/CMC/GO-f-COOH@Ag membrane presents exceptional photocatalytic properties for the catalytic degradation of methylene blue (MB) dye. Hence, the fabricated nanofibrous membrane would be an eco-friendly system for wastewater treatment under catalytic reaction.

In Vitro and In Vivo Characterization Methods for Evaluation of Modern Wound Dressings

Chronic wound management represents a major challenge in the healthcare sector owing to its delayed wound-healing process progression and huge financial burden. In this regard, wound dressings provide an appropriate platform for facilitating wound healing for several decades. However, adherent traditional wound dressings do not provide effective wound healing for highly exudating chronic wounds and need the development of newer and innovative wound dressings to facilitate accelerated wound healing. In addition, these dressings need frequent changing, resulting in more pain and discomfort. In order to overcome these issues, a wide range of affordable and innovative modern wound dressings have been developed and explored recently to accelerate and improve the wound healing process. However, a comprehensive understanding of various in vitro and in vivo characterization methods being utilized for the evaluation of different modern wound dressings is lacking. In this context, an overview of modern dressings and their complete in vitro and in vivo characterization methods for wound healing assessment is provided in this review. Herein, various emerging modern wound dressings with advantages and challenges have also been reviewed. Furthermore, different in vitro wound healing assays and in vivo wound models being utilized for the evaluation of wound healing progression and wound healing rate using wound dressings are discussed in detail. Finally, a summary of modern wound dressings with challenges and the future outlook is highlighted.

Sulfamic acid grafted to cross-linked chitosan by dendritic units: a bio-based, highly efficient and heterogeneous organocatalyst for green synthesis of 2,3-dihydroquinazoline derivatives

In this work, novel cross-linked chitosan by the G1 dendrimer from condensation of melamine and toluene-2,4-diisocyante terminated by sulfamic acid groups (CS-TDI-Me-TDI-NHSO₃H), as a bio-based and heterogeneous acidic organocatalyst, was designed and prepared. Also, the structure of the prepared organocatalyst was characterized by Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and thermogravimetric analysis/derivative thermogravimetry (TGA/DTA). Subsequently, the catalytic performance of the biobased and dendritic CS-TDI-Me-TDI-NHSO₃H, as a multifunctional solid acid, was evaluated for the preparation of 2,3-dihydroquinazoline derivatives through a three-component reaction by following green chemistry principles. Some of the advantages of this new protocol include high to excellent yields and short reaction times as well as easy preparation and remarkable catalyst stability of the introduced acidic organocatalyst. The CS-TDI-Me-TDI-SO₃H catalyst can be used for up to five cycles for the preparation of quinazoline derivatives with a slight decrease in its catalytic activity.

Scaffolds in the microbial resistant era: Fabrication, materials, properties and tissue engineering applications

Due to microbial infections dramatically affect cell survival and increase the risk of implant failure, scaffolds produced with antimicrobial materials are now much more likely to be successful. Multidrug-resistant infections without suitable prevention strategies are increasing at an alarming rate. The ability of cells to organize, develop, differentiate, produce a functioning extracellular matrix (ECM) and create new functional tissue can all be controlled by careful control of the extracellular microenvironment. This review covers the present state of advanced strategies to develop scaffolds with antimicrobial properties for bone, oral tissue, skin, muscle, nerve, trachea, cardiac and other tissue engineering applications. The review focuses on the development of antimicrobial scaffolds against bacteria and fungi using a wide range of materials, including polymers, biopolymers, glass, ceramics and antimicrobials agents such as antibiotics, antiseptics, antimicrobial polymers, peptides, metals, carbon nanomaterials, combinatorial strategies, and includes discussions on the antimicrobial mechanisms involved in these antimicrobial approaches. The toxicological aspects of these advanced scaffolds are also analyzed to ensure future technological transfer to clinics. The main antimicrobial methods of characterizing scaffolds’ antimicrobial and antibiofilm properties are described. The production methods of these porous supports, such as electrospinning, phase separation, gas foaming, the porogen method, polymerization in solution, fiber mesh coating, self-assembly, membrane lamination, freeze drying, 3D printing and bioprinting, among others, are also included in this article. These important advances in antimicrobial materials-based scaffolds for regenerative medicine offer many new promising avenues to the material design and tissue-engineering communities.

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Antibacterial, antifungal and antibiofilm scaffolds.

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Antimicrobial scaffold fabrication techniques.

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Antimicrobial biomaterials for tissue engineering applications.

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Antimicrobial characterization methods of scaffolds.

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Bone, oral tissue, skin, muscle, nerve, trachea, cardiac, among other applications.

Gallic Acid-Loaded Sodium Alginate-Based (Polyvinyl Alcohol-Co-Acrylic Acid) Hydrogel Membranes for Cutaneous Wound Healing: Synthesis and Characterization

Traditional wound dressings often cannot treat wounds caused by bacterial infections or other wound types that are insensitive to these wound treatments. Therefore, a biodegradable, bioactive hydrogel wound dressing could be an effective alternative option. The purpose of this study was to develop a hydrogel membrane comprised of sodium alginate, polyvinyl alcohol, acrylic acid, and gallic acid for treating skin wounds. The newly developed membranes were analyzed using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), sol-gel fraction, porosity, mechanical strength, swelling, drug release and data modelling, polymeric network parameters, biodegradation, and antioxidation (DPPH and ABTS) and antimicrobial activity against Gram-positive and negative bacteria. The results revealed that hydrogel membranes were crosslinked successfully and had excellent thermal stability, high drug loading, greater mechanical strength, and exhibited excellent biodegradation. Additionally, the swelling ability and the porosity of the surface facilitated a controlled release of the encapsulated drug (gallic acid), with 70.34% release observed at pH 1.2, 70.10% at pH 5.5 (normal skin pH), and 86.24% at pH 7.4 (wounds pH) in 48 h. The gallic acid-loaded hydrogel membranes showed a greater area of inhibition against Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli bacteria as well as demonstrated excellent antioxidant properties. Based on Franz cell analyses, the permeation flux of the drug from optimized formulations through mice skin was 92 (pH 5.5) and 110 (pH 7.4) μg/cm²·h^-1. Moreover, hydrogel membranes retained significant amounts of drug in the skin for 24 h, such as 2371 (pH 5.5) and 3300 µg/cm² (pH 7.4). Acute dermal irritation tests in rats showed that hydrogel membranes were nonirritating. Hydrogel membranes containing gallic acid could be an effective option for improving wound healing and could result in faster wound healing.

Multifunctional Bioactive Scaffolds from ARX-g-(Zn@rGO)-HAp for Bone Tissue Engineering: In Vitro Antibacterial, Antitumor, and Biocompatibility Evaluations

Advanced biomaterials are required with enhanced antibacterial and anticancer activities to obtain desirable biocompatibility during and after scaffold implantation in tissue engineering. Here, we report the development of a nanosystem by the hydrothermal method using different zinc (Zn) amounts and reduced graphene oxide (GO). Arabinoxylan, the nanosystem (Zn@rGO), and nanohydroxyapatite polymeric nanocomposites ARX-g-(Zn@rGO)/HAp were prepared by the free radical polymerization method, and porous bioactive scaffolds were fabricated via the freeze-drying technique. The structural, morphological, and elemental analyses of the bioactive scaffolds were conducted using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray analysis. The wetting behavior was studied by a water contact meter and swelling in aqueous and phosphate-buffered saline solutions at 37 °C. The degradation was also studied in the phosphate-buffered saline solution at 37 °C. The increase in Zn content increased the pore size, and hydrophobic behavior shifted to hydrophilic (AGZ-1 = 131.40° at 0 s and 120.60° at 10 s to AGZ-1 = 81.30° at 0 s and 69.20° at 10 s) with the increase in contact time. Maximum swelling was observed in deionized water (AGZ-1 = 52.87%, AGZ-4 = 90.20%), followed by phosphate-buffered saline (PBS; AGZ-1 = 44.80%, AGZ-4 = 67.90%) and electrolyte (AGZ-1 = 32.40%, AGZ-4 = 63.47%), and biodegradation in PBS media increased (AGZ-1 = 36.80%, AGZ-4 = 55.92%). Antimicrobial activities against severe infection-causing pathogens and antitumor activity against U87 cell lines showed exceptional results. Cell viability and cell proliferation studies were conducted against preosteoblast cell lines, and increased cell viability and proliferation were observed from AGZ-1 to AGZ-4. Antimicrobial and anticancer activities were enhanced with the increase of Zn content in the Zn@rGO system. The bioactive scaffolds with different formulations could be potential biomaterials to treat and regenerate defected bone tissue.

Preparation and Characterization of Alginate Hydrogel Fibers Reinforced by Cotton for Biomedical Applications

In this study, cotton-reinforced alginate hydrogel fibers were successfully synthesized using the wet spinning technique to improve hydrogel fibers' mechanical strength and durability. Structural, chemical, and mechanical properties of the prepared fibers were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray Diffraction, differential scanning calorimeter, and single fiber strength tester. Based on the results obtained from fourier transform infrared spectroscopy and x-ray Diffraction, cotton fibers have been successfully incorporated into the structure of the hydrogel fibers. It was seen from the differential scanning calorimeter results that the incorporation of fibers in the structure even enhanced the thermal stability of the fiber and is viable to be implanted in the human body. Cotton reinforcement in alginate hydrogel fibers increases the modulus up to 56.45 MPa providing significant stiffness and toughness for the hydrogel composite fiber. The tenacity of the fibers increased by increasing the concentration of alginate from 2.1 cN/Tex (1% w/v) to 8.16 cN/Tex (1.5% w/v). Fiber strength increased by 26.75% and water absorbance increased by 120% by incorporating (10% w/w) cotton fibers into the fibrous structure. It was concluded that these cotton-reinforced alginate hydrogel fibers have improved mechanical properties and liquid absorption properties suitable for use in various biomedical applications.

Physicochemical Properties of Cellulose-Based Hydrogel for Biomedical Applications

Hydrogels are three-dimensional network structures of hydrophilic polymers, which have the capacity to take up an enormous amount of fluid/water. Carboxymethyl cellulose (CMC) is a commercially available cellulose derivative that can be used for biomedical applications due to its biocompatibility. It has been used as a major component to fabricate hydrogels because of its superabsorbent nature. In this study, we developed carboxylic acid crosslinked carboxymethyl cellulose hydrogels for biomedical applications. The physicochemical, morphological, and thermal properties were analyzed to confirm the crosslinking of carboxymethyl cellulose. Fourier-transform infrared spectra confirmed the crosslinking of carboxymethyl cellulose with the presence of peaks due to an esterification reaction. The distinct peak at 1718 cm-1 in hydrogel samples is due to the carbonyl group vibrations of the ester bond from the crosslinking reaction. The total carboxyl content of the sample was measured with crosslinker immersion time. The swelling of crosslinked hydrogels showed an excellent swelling capacity for CG02 that is much higher than CG01 in water and PBS. Morphological analysis of the hydrogel showed it has a rough surface. The thermal degradation of hydrogel showed stability with respect to temperature. However, the mechanical analysis showed that CG01 has a higher compressive strength than CG01. The optimum swelling ratio and higher compressive strength of CG01 hydrogels could give them the ability to be used in load-bearing tissue regeneration. These results inferred that the carboxylic acid crosslinked CMC hydrogels could be a suitable matrix for biomedical or tissue-engineering applications with improved stability.

Thermo-Sensitive Poly (N-isopropylacrylamide-co-polyacrylamide) Hydrogel for pH-Responsive Therapeutic Delivery

Stimuli-response polymeric nanoparticles have emerged as a carrier system for various types of therapeutic delivery. In this study, we prepared a dual pH- and thermo-sensitive copolymer hydrogel (HG) system (PNIPAm-co-PAAm HG), using N-isopropyl acrylamide (NIPAm) and acrylamide (AAm) as comonomers. The synthesized PNIPAm-co-PAAm HG was characterized using various instrumental characterizations. Moreover, the PNIPAm-co-PAAm HG's thermoresponsive phase transition behavior was investigated, and the results showed that the prepared HG responds to temperature changes. In vitro drug loading and release behavior of PNIPAm-co-PAAm HG was investigated using Curcumin (Cur) as the model cargo under different pH and temperature conditions. The PNIPAm-co-PAAm HG showed pH and temperature-responsive drug release behavior and demonstrated about 65% Cur loading efficiency. A nearly complete release of the loaded Cur occurred from the PNIPAm-co-PAAm HG over 4 h at pH 5.5 and 40 °C. The cytotoxicity study was performed on a liver cancer cell line (HepG2 cells), which revealed that the prepared PNIPAm-co-PAAm HG showed good biocompatibility, suggesting that it could be applied as a drug delivery carrier. Moreover, the in vitro cytocompatibility test (MTT assay) results revealed that the PNIPAm-co-PAAm HG is biocompatible. Therefore, the PNIPAm-co-PAAm HG has the potential to be useful in the delivery of drugs in solid tumor-targeted therapy.

Bioactive scaffold (sodium alginate)-g-(nHAp@SiO2@GO) for bone tissue engineering

Globally, people suffering from bone disorders are steadily increasing and bone tissue engineering is an advanced approach to treating fractured and defected bone tissues. In this study, we have prepared polymeric nanocomposite by free-radical polymerization from sodium alginate, hydroxyapatite, and silica with different GO amounts. The porous scaffolds were fabricated using the freeze drying technique. The structural, morphological, mechanical, and wetting investigation was conducted by Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscope, universal tensile machine, and water contact angle characterization techniques. The swelling, biodegradation, and water retention were also studied. The biological studies were performed (cell viability, cell adherence, proliferation, and mineralization) against osteoblast cell lines. Scaffolds have exhibited different pore morphology SAG-1 (pore size = 414.61 ± 56 μm and porosity = 81.45 ± 2.17 %) and SAG-4 (pore size = 195.97 ± 82 μm and porosity = 53.82 ± 2.45 %). They have different mechanical behavior as SAG-1 has the least compression strength and compression modulus 2.14 ± 2.35 and 16.51 ± 1.27 MPa. However, SAG-4 has maximum compression strength and compression modulus 13.67 ± 2.63 and 96.16 ± 1.97 MPa with wetting behavior 80.70° and 58.70°, respectively. Similarly, SAG-1 exhibited the least and SAG-4 presented maximum apatite mineral formation, cell adherence, cell viability, and cell proliferation against mouse pre-osteoblast cell lines. The increased GO amount provides different multifunctional materials with different characteristics. Hence, the fabricated scaffolds could be potential scaffold materials to treat and regenerate fracture bone tissues in bone tissue engineering.

Dialdehyde Starch Nanocrystals as a Novel Cross-Linker for Biomaterials Able to Interact with Human Serum Proteins

In recent years, new cross-linkers from renewable resources have been sought to replace toxic synthetic compounds of this type. One of the most popular synthetic cross-linking agents used for biomedical applications is glutaraldehyde. However, the unreacted cross-linker can be released from the materials and cause cytotoxic effects. In the present work, dialdehyde starch nanocrystals (NDASs) were obtained from this polysaccharide nanocrystal form as an alternative to commonly used cross-linking agents. Then, 5-15% NDASs were used for chemical cross-linking of native chitosan (CS), gelatin (Gel), and a mixture of these two biopolymers (CS-Gel) via Schiff base reaction. The obtained materials, forming thin films, were characterized by ATR-FTIR, SEM, and XRD analysis. Thermal and mechanical properties were determined by TGA analysis and tensile testing. Moreover, all cross-linked biopolymers were also characterized by hydrophilic character, swelling ability, and protein absorption. The toxicity of obtained materials was tested using the Microtox test. Dialdehyde starch nanocrystals appear as a beneficial plant-derived cross-linking agent that allows obtaining cross-linked biopolymer materials with properties desirable for biomedical applications.

Advances in Biologically Applicable Graphene-Based 2D Nanomaterials

Climate change and increasing contamination of the environment, due to anthropogenic activities, are accompanied with a growing negative impact on human life. Nowadays, humanity is threatened by the increasing incidence of difficult-to-treat cancer and various infectious diseases caused by resistant pathogens, but, on the other hand, ensuring sufficient safe food for balanced human nutrition is threatened by a growing infestation of agriculturally important plants, by various pathogens or by the deteriorating condition of agricultural land. One way to deal with all these undesirable facts is to try to develop technologies and sophisticated materials that could help overcome these negative effects/gloomy prospects. One possibility is to try to use nanotechnology and, within this broad field, to focus also on the study of two-dimensional carbon-based nanomaterials, which have excellent prospects to be used in various economic sectors. In this brief up-to-date overview, attention is paid to recent applications of graphene-based nanomaterials, i.e., graphene, graphene quantum dots, graphene oxide, graphene oxide quantum dots, and reduced graphene oxide. These materials and their various modifications and combinations with other compounds are discussed, regarding their biomedical and agro-ecological applications, i.e., as materials investigated for their antineoplastic and anti-invasive effects, for their effects against various plant pathogens, and as carriers of bioactive agents (drugs, pesticides, fertilizers) as well as materials suitable to be used in theranostics. The negative effects of graphene-based nanomaterials on living organisms, including their mode of action, are analyzed as well.

pH-Responsive PVA/BC-f-GO Dressing Materials for Burn and Chronic Wound Healing with Curcumin Release Kinetics

Polymeric materials have been essential biomaterials to develop hydrogels as wound dressings for sustained drug delivery and chronic wound healing. The microenvironment for wound healing is created by biocompatibility, bioactivity, and physicochemical behavior. Moreover, a bacterial infection often causes the healing process. The bacterial cellulose (BC) was functionalized using graphene oxide (GO) by hydrothermal method to have bacterial cellulose-functionalized-Graphene oxide (BC-f-GO). A simple blending method was used to crosslink BC-f-GO with polyvinyl alcohol (PVA) by tetraethyl orthosilicate (TEOS) as a crosslinker. The structural, morphological, wetting, and mechanical tests were conducted using Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM), water contact angle, and a Universal testing machine (UTM). The release of Silver-sulphadiazine and drug release kinetics were studied at various pH levels and using different mathematical models (zero-order, first-order, Higuchi, Hixson, Korsmeyer–Peppas, and Baker–Lonsdale). The antibacterial properties were conducted against Gram-positive and Gram-negative severe infection-causing pathogens. These composite hydrogels presented potential anticancer activities against the U87 cell line by an increased GO amount. The result findings show that these composite hydrogels have physical-mechanical and inherent antimicrobial properties and controlled drug release, making them an ideal approach for skin wound healing. As a result, these hydrogels were discovered to be an ideal biomaterial for skin wound healing.

Multifunctional Arabinoxylan-functionalized-Graphene Oxide Based Composite Hydrogel for Skin Tissue Engineering

Wound healing is an important physiological process involving a series of cellular and molecular developments. A multifunctional hydrogel that prevents infection and promotes wound healing has great significance for wound healing applications in biomedical engineering. We have functionalized arabinoxylan and graphene oxide (GO) using the hydrothermal method, through cross-linking GO-arabinoxylan and polyvinyl alcohol (PVA) with tetraethyl orthosilicate (TEOS) to get multifunctional composite hydrogels. These composite hydrogels were characterized by FTIR, SEM, water contact angle, and mechanical testing to determine structural, morphological, wetting, and mechanical behavior, respectively. Swelling and biodegradation were also conducted in different media. The enhanced antibacterial activities were observed against different bacterial strains (E. coli, S. aureus, and P. aeruginosa); anticancer activities and biocompatibility assays were found effective against U-87 and MC3T3-E1 cell lines due to the synergic effect of hydrogels. In vivo activities were conducted using a mouse full-thickness skin model, and accelerated wound healing was found without any major inflammation within 7 days with improved vascularization. From the results, these composite hydrogels might be potential wound dressing materials for biomedical applications.

F-GO/sodium alginate composite hydrogels for tissue regeneration and antitumor applications

Biopolymers have attracted tremendous attention for wound applications. Since sodium alginate is a biopolymer, they offer excellent therapeutic options with long-term drug release and low side effects. To prepare multifunctional composite hydrogels with anticancer and tissue regeneration capabilities, sodium alginate (SA) and graphene oxide (GO) were covalently linked and crosslinked with tetraethyl orthosilicate (TEOS) by the solvothermal method. The structural and morphological results show that the hydrogels exhibit the desired functionality and porosity. The swelling of hydrogels in an aqueous and PBS medium was investigated. SGT-4 had the highest swelling in both aqueous and PBS media. Swelling and biodegradation of the hydrogel were inversely related. The drug release of SGT-4 was determined in different pH media (pH 6.4, 7.4, and 8.4) and the kinetics of drug release was determined according to the Higuchi model (R2 = 0.93587). Antibacterial activities were evaluated against severe infectious agents. Uppsala (U87) and osteoblast (MC3T3-E1) cell lines were used to determine the anticancer and biocompatibility of the composite hydrogels, respectively. These results suggest that the composite hydrogels could be used as wound dressings.